The exemplary embodiment relates to a biocompatible polymer composition which includes a phytochemical. In particular, it relates to a biocompatible polymer where the phytochemical is an isoflavone, such as genistein. The polymer composition finds particular application in forming dialysis membranes, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Hemodialysis is used for filtering impurities from the blood, for example, to provide an artificial replacement for lost kidney function. In hemodialysis, patient blood is typically pumped for repeated cycles through a dialyzer unit packed with hollow fiber bundles made-up of hydrophobic/hydrophilic polymer blends to reduce urea and uremic toxin concentration in blood to physiologically acceptable levels. However, there are problems associated with hemodialysis, such as an increase in oxidants in the blood and inflammatory responses due to long term exposure of the blood to a synthetic polymer surface. These complications are referred to as dialysis induced oxidative stress (DIOS), and membrane induced inflammation (MII) in blood and can result in cardiovascular problems and, in some cases, death. In DIOS, excess production of oxygen radicals can overpower the natural antioxidant defense mechanisms of the body. The bio-incompatibility of the polymeric hemodialysis membranes has been implicated as the primary source of generation of excessive reactive oxygen species (ROS), which contribute to DIOS. MII causes an immune response resulting from higher concentrations of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin (IL-6), and tumor necrosis factor-α (TNF-α). A dialysis patient generally undergoes supplemental drug therapy to counteract these effects. There remains a need for membranes that are capable of suppressing these long term ill-effects.
Surface modification techniques have been employed to produce biocompatible materials which are suited to use in hemodialysis membranes. These include polyethylene glycol grafting, albumin coatings, phospholipid mimicking surfaces, plasma treatments, fluorination, modification using anti-platelet agents like prostacyclin and fibrinolytic agents, and heparinizing the surface. Anti-bacterial surface treatments have also been proposed. However, problems remain.
The exemplary embodiment provides a biocompatible polymer composition suited to use in a hemodialysis membrane which can alleviate some of these problems.